I've just gotten my girlfriend an electric guitar. I was wondering whether I should; get an additional amplifier (I already have one for myself), or, sell the one I currently have (that only has one input), and buy an amplifier with two inputs? Thing is, I've got a really low budget of about $150USD, plus whatever I make from the amplifier I currently have, should I decide to sell it (I don't think it'll fetch too much, given that it is a dinky, low-end valvestate Marshall).
What amplifiers would you guys recommend? I'm not looking for any particularly spectacular model, knowing the limits of what $150USD+ can get, but perhaps people have some recommendations for nice practice amplifiers around that price range? As long as there's a decent clean sound, I'm good to go!

Thanks!